Bis-esters of 1,1-alkanediols with 6-beta-hydroxymethylpenicillanic acid 1,1-dioxide

ABSTRACT

Bis-Esters of 1,1-alkanediols with 6-beta(hydroxymethyl)penicillanic acid 1,1-dioxide and 6-betaacylaminopenicillanic acids are useful as antibacterial agents. Intermediates useful for the preparation of these compounds include halomethyl, alkylsulfonyloxymethyl and arylsulfonyloxymethylesters of 6-beta(hydroxymethyl)penicillanic acid 1,1-dioxide and 6-beta-aminopenicillanoyloxymethyl-6&#39;-beta-(hydroxymethyl)penicillanate 1,1-dioxide.

CROSS REFERENCE TO RELATED APPLICATION

This application is a division of copending application Ser. No.246,505, filed Mar. 23, 1981, now U.S. Pat. No. 4,342,768, which is acontinuation-in-part of application Ser. No. 086,864 filed Oct. 22, 1979now U.S. Pat. No. 4,287,181.

BACKGROUND OF THE INVENTION

One of the most well-known and widely used class of antibacterial agentsare the so-called beta-lactam antibiotics. These compounds arecharacterized in that they have a nucleus consisting of a 2-azetidinone(beta-lactam) ring fused to a thiazolidone, a dihydro-1,3-thiazine orother similar ring system. When the nucleus contains a thiazolidonering, the compounds are usually referred to generically as penicillins,whereas when the nucleus contains a dihydrothiazine ring, the compoundsare referred to as cephalosporins. Typical examples of penicillins whichare commonly used in clinical practice are benzylpenicillin (penicillinG), phenoxymethylpenicillin (penicillin V), ampicillin, amoxicillin,hetacillin and carbenicillin; typical examples of common cephalosporinsare cephalothin, cephalexin and cefazolin.

However, despite the wide use and wide acceptance of the beta-lactamantibiotics as valuable chemotherapeutic agents, they suffer from themajor drawback that certain members are not active against certainmicroorganisms. It is thought that in many instances this resistance ofa particular microorganism to a given beta-lactam antibiotic resultsbecause the microorganism produces a beta-lactamase. The lattersubstances are enzymes which cleave the beta-lactam ring of penicillinsand cephalosporins to give products which are devoid of antibacterialactivity. However, certain substances have the ability to inhibitbeta-lactamases, and when a beta-lactamase inhibitor is used incombination with a penicillin or caphalosporin, it can increase orenhance the antibacterial effectiveness of the penicillin orcaphalosporin against certain beta-lactamase producing microorganisms.It is considered that there is an enhancement of antibacterialeffectiveness when the antibacterial activity of a combination of abeta-lactamase inhibiting substance and a beta-lactam antibiotic issignificantly greater than the sum of the antibacterial activities ofthe individual components against beta-lactamase producingmicroorganisms.

The present invention relates to a series of bis-1,1-alkanediol estersof 6-beta-(hydroxymethyl)penicillanic acid 1,1-dioxide and penicillinscommonly used in clinical practice. These esters are readily hydrolyzedin vivo to yield the penicillin and 6-beta-(hydroxymethyl)penicillanicacid 1,1-dioxide, a particularly potent inhibitor of microbialbeta-lactamases which enhances the effectiveness of the penicillin. Theinvention further relates to intermediates useful in the preparation ofthese 1,1-alkanediol esters.

Bis-esters of beta-lactam antibiotics and beta-lactamase inhibitingsubstances have been the subject of earlier reports, in particular thebis 1,1-alkanediol esters of beta-lactam antibiotics and penicillanicacid 1,1-dioxide (British Patent Application No. 2,044,255 and U.S. Pat.No. 4,244,951). However, the present compounds show a broader spectrumof activity than these earlier compounds, for example showing a highlevel of activity against beta-lactamase producing strains ofPseudomonas aeruginosa and Enterobacter cloacal, organisms against whichthe earlier compounds show little or no activity.

SUMMARY OF THE INVENTION

Particularly valuable antibacterial compounds of the present inventionare of the formula ##STR1## including the pharmaceutically-acceptablesalts thereof, wherein R is 2-phenylacetamido, 2-phenoxyacetamido,D-2-amino-2-phenylacetamido, D-2-amino-2-(4-hydroxyphenyl)acetamido,2-carboxy-2-phenylacetamido, 2-carboxy-2-(2-thienyl)acetamido,2-carboxy-2-(3-thienyl)acetamido,D-2-(4-ethyl-2,3-dioxopiperazinocarbonylamino)-2-phenylacetamido or2,2-dimethyl-4-phenyl-5-imidazolidinon-1-yl; and R' is hydrogen ormethyl.

The expression "pharmaceutically-acceptable salts" is intended toencompass pharmaceutically-acceptable cation salts when the side chain Rcontains a carboxy group, and pharmaceutically-acceptable acid additionsalts when the side chain R contains an amino group.

Of the compounds (1), those compounds wherein R' is hydrogen arepreferred. Within this subgenus, the species most preferred are thosewherein R is:

D-2-amino-2-phenylacetamido;

2-carboxy-2-phenylacetamido;

D-2-amino-2-(4-hydroxyphenyl)acetamido; and

2-phenylacetamido.

Particularly valuable intermediates of the present invention arecompounds of the formula ##STR2## wherein R' is hydrogen or methyl andR" is amino or the D-form of ##STR3## wherein Y is hydrogen or hydroxyand Z is azido, benzyloxycarbonylamino or1-carbomethoxy-1-propen-2-ylamino.

Within this class of intermediates the preferred compounds have R' ashydrogen; within this subgenus the most preferred compounds are thosewherein R" is:

amino;

D-2-azido-2-phenylacetamido; or

D-2-(benzyloxycarbonylamino)-2-(p-hydroxyphenyl)acetamido.

Other valuable intermediates are of the formula ##STR4## wherein n iszero or an integer of value 1 or 2; R' is hydrogen or methyl; and X ischloro, bromo, iodo, (C₁ -C₄)alkylsulfonyloxy, benzenesulfonyloxy ortoluenesulfonyloxy. In this series preferred compounds have R' ashydrogen. Within this subgenus the most preferred compounds have:

n as 0 and X as chloro;

n as 1 and X as chloro;

n as 2 and X as chloro; and

n as 2 and X as iodo.

Yet other valuable intermediates are of the formulae ##STR5## wherein R'is hydrogen or methyl and X is chloro, bromo, iodo, (C₁-C₄)alkylsulfonyloxy, benzenesulfonyloxy or toluenesulfonyloxy. Thepreferred compound in this series is of the formula (4a) and has R' ashydrogen and X as chloro.

Also encompassed by the present invention are pharmaceuticalcompositions of the antibacterial compounds of the formula (1) suitablefor treating a bacterial infection in a mammalian subject. The presentcompounds can be dosed either parenterally or orally, but areparticularly advantageous when given via the oral route.

Further encompassed by the present invention is a method for treatingbacterial infections in a mammal which comprises administering to saidmammal an antibacterially effective amount of an antibacterial compoundof the formula (1). The preferred route of administration for saidtreatment is oral. The compounds are well absorbed and are hydrolyzed invivo to the penicillin antibiotic and the beta-lactamase inhibitor,which then strongly potentiates the activity of the penicillin against aparticularly broad spectrum of pathogenic organisms.

DETAILED DESCRIPTION OF THE INVENTION

This invention relates to derivatives of6-beta-(hydroxymethyl)penicillanic acid 1,1-dioxide, which isrepresented by the following structural formula ##STR6## In formula (6),broken line attachment of a substituent to the bicyclic nucleusindicates that the substituent is below the plane of the bicyclicnucleus. Such a substituent is said to be in the alpha-configuration.Conversely, heavy line attachment of a substituent to the bicyclicnucleus indicates that the substituent is attached above the plane ofthe nucleus. This latter configuration is referred to as thebeta-configuration.

Using this system, the compounds of formulae (1) and (2) are named as6-beta-substituted derivatives of 1-(penicillanoxyloxy)alkyl6'-beta-(hydroxymethyl)penicillanate 1',1'-dioxide (7), in which the1-position of the alkyl group and the 1-position of the first ringsystem is unambiguous under the nomenclature system, but in which primedand unprimed locants are used to distinguish between the two ringsystems, viz: ##STR7##

In one method of the present invention certain compounds of formulae (1)and (2) are prepared by reacting a carboxylate salt of the formula##STR8## with a compound of the formula ##STR9## wherein R' and X are aspreviously defined; R'" is 2-phenylacetamido, 2-phenoxyacetamido,D-2-(4-ethyl-2,3-dioxopiperazinocarbonylamino-2-phenylacetamido,2,2-dimethyl-4-phenyl-5-imidazolidinon-1-yl,2-benzyloxycarbonyl-2-(2-thienyl)acetamido, benzyloxycarbonylamino, or##STR10## wherein Y and Z are as defined above; and M is a carboxylatesalt forming cation. A variety of cations can be used to form thecarboxylate salt in the compound of formula (8), but salts which arecommonly used include: alkali metal salts, such as sodium and potassiumsalts; alkaline earth metal salts, such as calcium and barium salts;tertiary amine salts, such as trimethylamine, triethylamine,tributylamine, diisopropylethylamine, N-methylmorpholine,N-methylpiperidine, N-methylpyrrolidine, N,N'-dimethylpiperazine and1,2,3,4-tetrahydroquinoline; and quaternary ammonium salts such astetrabutylammonium salts. The quaternary ammonium salts are preferredsalts, since the reaction between compounds of the formulae (8) and (9)is unusually rapid and degradation of the beta-lactams is thereby keptto an absolute minimum.

Said reaction between a compound of formula (8) and a compound offormula (9) is usually carried out by contacting the reagents in apolar, organic solvent, at a temperature in the range from about 0° toabout 80° C., and preferably from 0° to 35° C. The compounds of formulae(8) and (9) are usually contacted in substantially equimolarproportions, but an excess of either reagent, for example up to aten-fold excess, can be used. A wide variety of solvents can be used,but it is usually advantageous to use a relatively polar solvent, sincethis has the effect of speeding up the reaction. A low boiling solvent,readily removed by vacuum stripping is also preferred. Typical solventswhich can be used include acetone, N,N-dimethylformamide,N,N-dimethylacetamide and N-methylpyrrolidone. The reaction time variesaccording to a number of factors, but at about 25° C. reaction times ofa few minutes to several hours, e.g., 12 to 24 hours, are commonly used,depending particularly on the values of M and X. When M is quaternaryammonium (e.g., tetrabutylammonium) and X is iodo, advantageously shortreaction times (e.g., 3-30 minutes) can generally be used. Reactions areconveniently monitored by standard silica gel thin layer chromatographicmethods, specifically exemplified below. When X is chloro or bromo, itis sometimes advantageous to add up to about one molar equivalent of analkali metal iodide, which has the effect of speeding up the reaction.

It will be evident from the above discussion that when the desiredantibacterial compound (1) contains a carboxy group or an amino group, aprotected or precursor form of the carboxy or amino group is employed.Conveniently these are such groups as a benzyl ester of the carboxygroup (benzyloxycarbonyl), an azido group, or a benzyloxycarbonylamino(carbobenzoxyamino) group which are readily hydrogenolyzed,respectively, to carboxy, amino and amino. These hydrogenolyses arecarried out by methods well-known in the art, viz., hydrogenation overan appropriate catalyst, such as palladium, platinum, or rhodium,optionally on a carrier such as carbon, calcium carbonate, or alumina,in an inert solvent, in such manner that degradation is minimized. Thusconditions are preferably near-neutral at ambient temperature or lower,and conveniently, at low to moderate pressure (e.g., 1 to 7atmospheres). Higher pressures, e.g., up to 70 atmospheres, can be usedbut offer no advantage. By "inert solvent" is meant one which willfinitely solubilize the starting material, without significantlyreacting with starting material(s), product(s) or reagent(s) (in thiscase hydrogen and catalyst). The preferred solvents for thehydrogenolysis are also those which are volatile and in which product isalso soluble, so that product can be recovered by simple evaporation invacuo (or freeze drying, as appropriate) of the filtrate after recoveryof catalyst. The preferred catalyst for the present hydrogenolysis ispalladium on carbon. Optimal conditions (e.g., time, level of catalyst,batch of catalyst) for the hydrogenolysis of any given compound of thepresent invention are readily determined by monitoring with thin-layerchromatography, using methods as detailed in specific Examples.

The starting compounds of the formula (8) are well known in thepenicillin art, either in the form of the free acids or in the form ofvarious metal salts. The preferred salts; i.e., the quaternary ammoniumsalts, of the compounds of formula (8) are readily prepared by reactionof a molar equivalent of the corresponding quaternary ammonium hydroxidewith the free acid form of (8) in a two phase, aqueous-organic system.The quaternary salt is isolated by simple evaporation of the organiclayer; thus, a low boiling solvent such as methylene chloride ispreferred.

The starting compounds of the formula (9) are conveniently prepared from6,6-dibromopenicillanic acid according to methods detailed in thespecific Examples below, employing intermediates of the formulae (3),(4a) and (4b) depicted above.

A variation of the foregoing method of preparing a compound of formula(7) involves reaction of a compound of the formula ##STR11## with acompound of the formula (11) ##STR12## wherein R', R'", M and X are asdefined previously, employing reaction conditions as defined above forthe reverse reaction. In this case when X is chloro, bromo or iodo, thestarting esters (11) are prepared by reaction of the corresponding metalsalt with ICH₂ X' wherein X' is chloro, bromo or iodo, and when X is(C₁₋₄)alkylsulfonyloxy, benzenesulfonyloxy or toluenesulfonyloxy, byreaction with the appropriate reactant CH₂ (OSO₂ R°)₂ wherein R° ismethyl, p-tolyl, phenyl or n-butyl. Said reactants, if not known, areprepared as described by Emmons et al., J. Am. Chem. Soc. 75, 2257(1953). The starting compound (10) is prepared by hydrogenolysis ofbenzyl 6-beta-(hydroxymethyl)penicillanate 1,1-dioxide which in turn isderived drom 6,6-dibromopenicillanate according to methods detailed inspecific Examples 1-3 below.

In yet another method according to the present invention, compounds ofthe formula (7) are prepared by acylation of the compound of the formula##STR13## using a variety of methods well known in the penicillin art.For example, compound (12) is reacted with essentially one equivalent ofan acid chloride such as phenylacetyl chloride, phenoxyacetyl chloride,or the mono acid chloride of phenylmalonic acid to yield, respectivelyand directly, compounds of the formula (1) wherein R is2-phenylacetamido, 2-phenoxyacetamido or 2-carboxy-2-phenylacetamido.The reaction is conveniently carried out in an anhydrous organic solventin the presence of a molar equivalent of a tert-amine such astriethylamine or N-methylmorpholine. Many solvents are suitable, but lowboiling solvents such as methylene chloride or acetone are preferred. Asa further Example, the amine (12) is coupled with the appropriate acidusing standard mixed anhydride procedures or dehydrating agents such ascarbodiimide, again using conditions, reagents and methodology wellknown in the penicillin art.

The hetacillin analogs, i.e., the compounds of the formula (1) wherein Ris 2,2-dimethyl-4-phenyl-5-imidazolidinon-1-yl, are alternativelyprepared by allowing the ampicillin analog, i.e., the compound of theformula (1) wherein R is D-2-amino-2-phenylacetamido, to stand inacetone at ambient temperature for 2-3 days.

The pharmaceutically-acceptable cationic salts of those compounds of thepresent invention having a free carboxylic acid group are readilyprepared by standard methods. For example, an equivalent of thecorresponding cationic hydroxide, carbonate or bicarbonate is combinedwith the carboxylic acid in an organic or aqueous solvent. The salt isisolated by concentration and/or the addition of a non-solvent. Ifdesired, the salt can generally be isolated directly from a reactionmixture, without isolation of the free acid form.Pharmaceutically-acceptable cationic salts include, but are not limitedto, those formed with sodium, potassium, calcium,N,N'-dibenzylethylenediamine, N-methylglucamine and diethanolamine.

The pharmaceutically-acceptable acid addition salts of those compoundsof the present invention having a free amino group are also readilyprepared by standard methods. For example, an equivalent of the acid iscombined with amine in an organic or an aqueous solvent. The salt isisolated by concentration and/or the addition of a non-solvent. Ifdesired, the salt can generally be isolated directly from a reactionmixture, without isolation of the free amine.Pharmaceutically-acceptable acid addition salts include, but are notlimited to, hydrochloric acid, sulfuric acid, nitric acid, phosphoricacid, citric acid, maleic acid, succinic acid, p-toluenesulfonic acidand methanesulfonic acid.

The utility of bis-ester compounds of the formula (1) is asexceptionally broad spectrum, systemic antibacterial agents. Thesecompounds are useful clinically in the treatment of mammalian infectionscaused by any one of this broad spectrum of sensitive bacteria. Thesystemic utility of these compounds results from their in vivohydrolysis to the mixture of penicillin antibiotic and, the potentbeta-lactamase inhibitor, viz., [6-beta-(hydroxymethyl)penicillanic acid1,1-dioxide] of the formula (6).

The ultimate clinical utility of the bis-ester compounds againstparticular pathogenic bacteria is reflected by in vitro measurements ofthe activity of the compound (6) against bacterially derivedbeta-lactamases, as well as by measuring the minimum inhibitoryconcentrations of a 1:1 combination of the penicillin with thebeta-lactamase inhibitory compound (6). The detailed description andtypical results of such studies follows.

The compounds of the present invention are thus evaluated in vitro bythe ability of the compound (13) to inhibit the hydrolysis of certainbeta-lactam antibiotics by beta-lactamase enzymes. The hydrolysis ofampicillin and penicillin G was determined by the microiodometric methodof Novick [Biochem, J. 83, 236 (1962)]. Conditions for this assay are0.5 M potassium phosphate, pH 6.5 and 37° C. Reactions were initiated bythe addition of the cell-free beta-lactamase, except in the case ofpreincubation experiments in which the inhibitor and enzyme wereincubated together in the assay mixture for 10 minutes before initiationof the reaction by addition of substrate. With the cell-free extracts ofStaphylococcus aureus, Escherichia coli, Klebsiella pneumoniae andPseudomonas aeruginosa, the substrate was ampicillin at 33 micro M (13microg./ml). Typical specific activities of the beta-lactamasepreparations were, respectively, 6,019, 88,970, 260 and 76 micromol/hr.per mg. of protein. Penicillin G (33 micromol) was the substrate usedwith the Enterobacter cloacae beta-lactamase, which showed a typicalspecific activity of 10,080 micromol/hr. per mg of protein.

Cell-free extracts were prepared by sonic treatment (using three 30-sbursts at 4° C. except for S. aureus, which was broken with a Frenchpress) of cultures grown in brain heart infusion on a rotary shakerincubator. For the S. aureus, P. aeruginose, and E. cloacae strains, denovo synthesis of beta-lactamase was induced by growing a log-phaseculture in the presence of a sublethal concentration of penicillin G at100, 1,000, and 300 microg./ml, respectively, for 2.5 hr.

The beta-lactamase inhibiting activities of the compound (6) and ofsodium penicillanic acid 1,1-dioxide are summarized in Table I.Especially noteworthy is the activity of compound (A) againstbeta-lactamase producing strains of Pseudomonas aeruginosa andEnterobacter cloacae against which the earlier beta-lactamase inhibitor,penicillanic acid 1,1-dioxide, shows at best a low order of activity.

                  TABLE I                                                         ______________________________________                                        Activity of Compounds As Inhibitors of                                        Cell Free Beta-Lactamases                                                     A. 6-beta-(Hydroxymethyl)penicillanic acid 1,1-                               dioxide (as calcium salt).                                                    B. Penicillanic acid 1,1-dioxide (as sodium salt)                                                                % Inhibi-                                                                     tion Beta- -Source of Antibiotic Inhibi                                       tor Lactam                                 Beta-Lactamsase                                                                          (conc.)    A/B    (conc.) Hydrolysis                               ______________________________________                                        Staphylococcus                                                                           Ampicillin                                                         aureus 01A400                                                                            (33 μM) A      66   μM                                                                              98.3                                                                16.5      78.8                                                                1.0       39.3                                                         B      66        100                                                                 16.5      95                                                                  1.0       0                                      Escherichia                                                                              Ampicillin                                                         coli 51A129                                                                              (33 μM) A      66        100                                                                 16.5      100                                                                 1.0       95.7                                                                0.67      92.1                                                         B      66        100                                                                 16.5      100                                                                 1.0       97.0                                   Klebsiella Ampicillin                                                         pneumoniae (33 μM) A      66        100                                    53A129                       16.5      100                                                                 1.0       81.2                                                         B      66        100                                                                 16.5      100                                    Pseudomonas                                                                              Penicillin G                                                        aeruginosa                                                                              (33 μM) A      66   μM                                                                              98.8                                   52A104                       16.5      93.4                                                                1.0       21.7                                                         B      66        0                                                 Ampicillin                                                                    (33 μM) B      66        27.5                                                                16.5      5.0                                    Enterobacter                                                                             Penicillin G                                                       cloacae 67B009                                                                           (33 μM) A      66        77.0                                                                16.5      52.0                                                                1.0       11.4                                                         B      66        0                                                                   16.5      0                                                                   1.0       0                                                                   66.sup.a  26                                     ______________________________________                                         .sup.a Preincubation (see text)                                          

The in vitro activity of the compounds of the present invention isdemonstrated by measuring the minimum inhibitory concentrations (MIC's)in mcg/ml of compound (6) together with the penicillin against a varietyof microorganisms. The procedure which is followed is the onerecommended by the International Collaborative Study on AntibioticSensitivity Testing [Ericcson and Sherris, Acta. Pathologica etMicrobiologia Scandinav, Supp. 217, Sections A and B: 64-68 (1971)], andemploys brain heart infusion (BHI) agar and the inocula replicatingdevice. Overnight growth tubes are diluted 100 fold for use as thestandard inoculum (20,000-10,000 cells in approximately 0.002 ml areplaced on the agar surface; 20 ml of BHI agar/dish). Twelve 2 folddilutions of the test compound are employed, with initial concentrationof the test drug being 200 mcg/ml. Single colonies are disregarded whenreading tubes after 18 hrs. at 37° C. The susceptibility (MIC) of thetest organism is accepted as the lowest concentration of compoundcapable of producing complete inhibition of growth as judged by thenaked eye. The manner in which the said compounds of the formula (B)increase the effectiveness of a beta-lactam antibiotic can beappreciated by reference to experiments in which the MIC of a givenantibiotic alone, and a compound of the formula (6) alone, are measured.These MIC's are then compared with the MIC values obtained with acombination of the given antibiotic and the compound of the formula (6).When the antibacterial potency of the combination is significantlygreater than would have been predicted from the potencies of theindividual compounds, this is considered to constitute enhancement ofactivity. The MIC values of combinations are measured using the methoddescribed by Barry and Sabath in "Manual of Clinical Microbiology",edited by Lenette, Spaulding and Truant, 2nd Edition, 1974, AmericanSociety for Microbiology.

Results of experiments illustrating that the compound of the formula (6)enhances the effectiveness of ampicillin are reported in Table II. Forpurposes of comparison data on the earlier beta-lactamase inhibitor,penicillanic acid 1,1-dioxide, are included. The enhanced spectrum andpotency (synergy or pronounced synergy) of compound (6) will be noted.

                                      TABLE II                                    __________________________________________________________________________    MIC Values for 1:1 Mixtures of                                                Ampicillin and beta-Lactamase Inhibitors                                      C.       6-beta-(Hydroxymethyl)penicillanic acid 1,1-Dioxides                          (sodium salt)                                                        D.       Penicillanic acid 1,1-dioxide (sodium salt)                          E.       Ampicillin                                                                     MIC Values                                                                            Response.sup.a                                                                      MIC Values                                                                            Response.sup.a                                Microoganism                                                                            D   1:1D:E                                                                            D     C   1:1C:E                                                                            C                                             __________________________________________________________________________    Staphylococcus                                                                aureus 01A005                                                                           100 ≦0.2                                                                       NT    >200                                                                              0.39                                                                              AT                                            Staphylococcus                                                                aureus 01A400                                                                           200 3.12                                                                              PS    >200                                                                              3.12                                                                              PS                                            Escherichia                                                                   coli 51A266                                                                             25  3.12                                                                              N     50  3.12                                                                              N                                             Citrobacter                                                                   diversus 70C031                                                                         200 12.5                                                                              PS    200 25  PS                                            Escherichia                                                                   coli-R 51A129                                                                           200 100 A     50  12.5                                                                              S                                             Pseudomonas                                                                   aeruginosa 52A104                                                                       >200                                                                              >100                                                                              NT    >200                                                                              100 S                                             Klebsiella                                                                    pneumoniae 53A079                                                                       50  12.5                                                                              S     50  6.25                                                                              PS                                            Proteus morgani                                                               57G001    200 12.5                                                                              PS    >200                                                                              1.56                                                                              PS                                            Serratia                                                                      marcescens 63A095                                                                       200 6.25                                                                              PS    200 6.25                                                                              PS                                            Enterobacter                                                                  cloacae 67B009                                                                          100 25  S     100 12.5                                                                              PS                                            __________________________________________________________________________     .sup.a PS = Pronounced Synergy                                                S = Synergy                                                                   A = Additive                                                                  N = Nothing                                                                   AT = Antagonism                                                               NT = No Test                                                             

When using an antibacterial compound of this invention in a mammal,particularly man, the compound can be administered alone, or it can bemixed with other antibiotic substances and/orpharmaceutically-acceptable carriers or diluents. Said carrier ordiluent is chosen on the basis of the intended mode of administration.For example, when considering the preferred oral mode of administration,an antibacterial compound of this invention can be used in the form oftablets, capsules, lozenges, troches, powders, syrups, elixirs, aqueoussolutions and suspensions, and the like, in accordance with standardpharmaceutical practice. The proportional ratio of active ingredient tocarrier will naturally depend on the chemical nature, solubility andstability of the active ingredient, as well as the dosage contemplated.In the case of tablets for oral use, carriers which are commonly usedinclude lactose, sodium citrate and salts of phosphoric acid. Variousdisintegrants such as starch, and lubricating agents, such as magnesiumstearate, sodium lauryl sulfate and talc, are commonly used in tablets.For oral administration in capsule form, useful diluents are lactose andhigh molecular weight polyethylene glycols, e.g., polyethylene glycolshaving molecular weights of from 2000 to 4000. When aqueous suspensionsare required for oral use, the active ingredient is combined withemulsifying and suspending agents. If desired, certain sweetening and/orflavoring agents can be added.

As indicated earlier, the antibacterial compounds of this invention areof use in human subjects and the daily dosages to be used will notdiffer significantly from other, clinically-used, penicillinantibiotics. The prescribing physician will ultimately determine theappropriate dose for a given human subject, and this can be expected tovary according to the age, weight, and response of the individualpatient as well as the nature and the severity of the patient'ssymptoms. The compounds of this invention will normally be used orallyand parenterally at dosages in the range from about 5 to about 100 mgper kilogram of body weight per day, usually in divided doses. In someinstances it may be necessary to use doses outside these ranges.

The present invention is illustrated by the following examples. However,it should be understood that the invention is not limited to thespecific details of these examples.

EXAMPLE 1 Chloromethyl 6,6-Dibromopenicillanate

6,6-Dibromopenicillanic acid [Clayton, J. Chem. Soc. C, p. 2123 (1969);25 g] was combined with 100 ml of methylene chloride and 25 ml of waterand the pH adjusted to 8.0 with 40% tetrabutylammonium hydroxide over aperiod of 15 minutes. The methylene chloride layer was separated and theaqueous layer extracted with three 3.5 ml portions of fresh methylenechloride. The methylene chloride layers were combined, dried overanhydrous sodium sulfate, filtered, and evaporated in vacuo to yieldtetrabutylammonium 6,6-dibromopenicillanate (39.0 g) as a viscous oil.The salt was combined with 125 ml of chloroiodomethane and the mixturestirred for 16 hours, concentrated to dryness in vacuo and the residuechromatographed on 1 kg of silica gel with 19:1 toluene: ethyl acetateas eluant and tlc monitoring [Rf 0.75 (1:1 hexane:ethyl acetate)]. Pureproduct fractions were combined, evaporated to dryness, and the residuerecrystallized from ether-petroleum ether to yield the title product intwo crops (14.1 g and 1.2 g); pnmr/CDCl₃ /delta (ppm) 1.6 (s, 3H), 1.75(s, 3H), 4.62 (s, 1H), 5.8 (dd, 2H), 5.82 (s, 1H); m.p. 105°-106° C.

By the same method, but substituting 1-chloro-1-iodoethane forchloroiodomethane, 1-chloroethyl 6,6-dibromopenicillanate is prepared.

By the same method, but substituting methylene bis-mesylate, methylenebis-tosylate, methylene bis(phenylsulfonate) or methylenebis(n-butylsulfonate) for chloroiodomethane, the following compounds areprepared:

mesyloxymethyl 6,6-dibromopenicillanate;

benzenesulfonyloxymethyl 6,6-dibromopenicillanate; and

tosyloxymethyl 6,6-dibromopenicillanate.

EXAMPLE 2 Chloromethyl 6-alpha-Bromo-6-beta-(hydroxymethyl)penicillanateand Chloromethyl 6-beta-Bromo-6-alpha-(hydroxymethyl)penicillanate

The title compound of the preceding Example (14.1 g) was combined with175 ml of dry tetrahydrofuran and cooled to -78° C. tert-Butylmagnesiumchloride (12.8 ml of 2.7 M in tetrahydrofuran) was added dropwise over10 minutes, while maintaining the temperature less than -65° C. Thereaction mixture was stirred for an additional 30 minutes at -78° C. Dryparaformaldehyde (45 g) heated at 150° C., under nitrogen, with an oilbath, was fed as formaldehyde by a slow stream of nitrogen into thereaction mixture over a 4 hour period. Acetic acid (5 ml) was added tothe cold reaction mixture, which was then warmed to room temperature,concentrated in vacuo, taken up in ethyl acetate, and washedsequentially with 200 ml 1 N hydrochloric acid, 2×100 ml of water and100 ml of saturated brine, dried over anhydrous sodium sulfate, andconcentrated to an oil. The oil was chromatographed on 600 g silica gelusing 9:1 toluene:ethyl acetate and then 4:1 toluene:ethyl acetate aseluant and tlc monitoring. Title products were obtained in about 1:5ratio of beta-hydroxymethyl to alpha-hydroxymethyl as an oil [5.2 g; Rf0.12, 0.18 (4:1 toluene:ethyl acetate); pnmr/CDCl₃ /delta (ppm) 1.58 (s,3H), 1.7 (s, 3H), 2.4-2.85 (m, 1H), 4.13 (broad s, 2H), 4.54 (s, 1H),5.52 (s, 1H), 5.75 (dd, 2H)].

By the same method the 1-chloroethyl ester of the preceding Example isconverted to 1-chloroethyl6-alpha-bromo-6-beta-(hydroxymethyl)penicillanate and 1-chloroethyl6-beta-bromo-6-alpha(hydroxymethyl)penicillanate.

By the same method the sulfonyloxymethyl esters of the preceding Exampleare converted to the corresponding mesyloxymethyl,benzenesulfonyloxymethyl and tosyloxymethyl esters.

EXAMPLE 3 Chloromethyl 6-beta-(Hydroxymethyl)penicillanate

The mixture of title products of the preceding Example (4.5 g, 12.5mmoles) combined with benzene (75 ml) and tributyltin hydride (3.48 ml,13.1 mmoles) and heated to reflux. Tlc monitoring indicated reaction wascomplete within 2 hours. The reaction mixture was cooled andconcentrated in vacuo to a viscous oil which gave a gum on triturationwith hexane. The gum was chromatographed on 200 g of silica gel elutingwith 1:1 toluene:ethyl acetate and collecting 25 ml fractions. Cleanproduct fractions 19-32 were combined and evaporated to yield the titleproduct as a viscous oil [2.8 g; ir (nujol) 1775 cm⁻¹ ; pnmr/CDCl₃/delta(ppm) 1.56 (s, 3H), 1.68 (s, 3H), 2.18-2.42 (m, 1H), 3.78-4.12 (m,3H), 4.4 (s, 1H), 5.42 (d, 1H), 5.74 (dd, 2H); Rf 0.34 (1:1toluene:ethyl acetate)].

By the same method, the mixture of 1-chloroethyl esters of the precedingExample is converted to 1-chloroethyl6-beta-(hydroxymethyl)penicillanate.

By the same method, the sulfonyloxymethyl esters of the precedingExample are converted to the corresponding mesyloxymethyl,benzenesulfonyloxymethyl and tosyloxymethyl esters.

EXAMPLE 4 Chloromethyl 6-beta-(Hydroxymethyl)penicillanate 1,1-Dioxide

The title product of the preceding Example (2.8 g.) was combined withethyl acetate (50 ml) and cooled to 0° C. m-Chloroperbenzoic acid (2.24g) was added. After 15 minutes the reaction mixture was checked by tlc;complete conversion to the 1-oxide [Rf 0.09 (1:1 toluene:ethyl acetate)]was indicated. Additional m-chloroperbenzoic acid (2.24 g) was added andthe mixture stirred for 16 hours at room temperature, by which time tlcindicated complete conversion to the dioxide. Water (50 ml) was added tothe reaction mixture and any excess peroxides destroyed with sodiumbisulfite. The pH was adjusted to 7.5 and the organic layer separated,washed sequentially with 25 ml portions of saturated sodium bicarbonate,water and brine, dried over anhydrous sodium sulfate, filtered, andconcentrated to yield the title product as a gum [2.6 g; ir (nujol) 1780cm⁻¹ pnmr/CDCl₃ /delta(ppm) 1.48 (s, 3H), 1.62 (s, 3H), 2.8-3.15 (broads, 1H), 4.2 (broad s, 2H), 4.08-4.5 (m, 1H), 4.5 (s, 1H), 4.68-4.83 (m,1H), 5.8 (dd, 2H)].

By the same method the 1-chloroethyl ester of the preceding Example isconverted to 1-chloroethyl 6-beta-(hydroxymethyl)penicillanate1,1-dioxide.

By the same method the sulfonyloxymethyl esters of the preceding Exampleare converted to the corresponding mesyloxymethyl,benzenesulfonyloxymethyl and tosyloxymethyl esters.

EXAMPLE 5 Iodomethyl 6-beta-(Hydroxymethyl)penicillanate 1,1-Dioxide

Title product of the preceding Example (2.4 g) was combined with 30 mlof acetone and sodium iodide (5.77 g) and the mixture stirred for 16hours. The reaction mixture was concentrated in vacuo to oily solids,which were distributed between 75 ml of ethyl acetate and 50 ml ofwater. The ethyl acetate was separated, washed in sequence with two 25ml portions of water and one 25 ml portion of brine, dried overanhydrous sodium sulfate, filtered and concentrated in vacuo. Theresidue was chromatographed on 200 g of silica gel, eluting with 7:3ethyl acetate:methylene chloride and collecting 20 ml fractions. Cleanproduct-containing fractions 14-25 were combined and evaporated to yieldtitle product as a tacky foam [2.4 g; ir (nujol) 1780 cm⁻¹ ; Rf 0.64(7:3 ethyl acetate:methylene chloride); pnmr/CDCl₃ /delta(ppm) 1.48 (s,3H), 1.6 (s, 3H), 2.8-3.15 (broad s, 1H), 4.2 (broad s, 2H), 4.1-4.42(m, 1H), 4.68-4.8 (m, 1H), 5.94 (dd, 2H)].

By the same method, extending the reaction time to 24 hours, the1-chloroethyl ester of the preceding Example is converted to 1-iodoethyl6-beta-(hydroxymethyl)penicillanate 1,1-dioxide.

By the same method, substituting sodium bromide for sodium iodide andextending the reaction time to 32 hours, bromomethyl6-beta-(hydroxymethyl)penicillanate 1,1-dioxide is prepared.

The title product is also prepared by reacting the correspondingmesyloxymethyl, benzenesulfonyloxymethyl and tosylsulfonyloxymethylesters with sodium iodide, but again extending the reaction time to 24hours.

EXAMPLE 6 6-beta-(D-2-Azido-2-phenylacetamido)penicillanoyloxymethyl6'-beta-(Hydroxymethyl)penicillanate 1',1'-Dioxide

A mixture of 3.5 g of 6-(D-2-alpha-azidophenylacetamido)penicillanicacid sodium salt in 20 ml of methylene chloride and 20 ml of water wastreated with sufficient 6 N hydrochloric acid to give a pH of 2.0.Tetrabutylammonium hydroxide (40% in water) was gradually added untilthe pH was 7.0. The organic phase was separated and the aqueous layerfurther extracted (2×20 ml) with fresh methylene chloride. The methylenechloride layers were combined, dried over sodium sulfate andconcentrated under vacuum to give 4.2 g of the correspondingtetrabutylammonium salt.

The tetrabutylammonium salt (1.65 g, 2.7 mmmoles) and the iodomethylester of the preceding Example (1.07 g, 2.7 mmoles) were combined in 20ml of acetone and stirred to dissolve. Tlc monitoring (1:1 ethylacetate:toluene) indicated that the reaction was almost complete within3 minutes of dissolution. After an additional 10 minutes, the reactionmixture was evaporated in vacuo to a foam which was chromatographed onsilica gel with 3:2 methylene chloride:ethyl acetate as eluant,collecting 20 ml fractions. Clean product fractions (tlc) were combinedand concentrated in vacuo to yield title product as a foam [1.7 g; Rf0.12 (1:1 ethyl acetate:toluene), 0.43 (3:2 methylene chloride:ethylacetate), 0.5 (1:1 methylene chloride:ethyl acetate); pnmr/CDCl₃/delta(ppm) 1.4, 1.5, 1.54, 1.61 (4s, 4×3H), 2.3-2.6 (m, 1H), 4.0-4.5(m, 3H), 4.4 (s, 2H), 5.0 (s, 1H), 5.4-5.8 (m, 2H), 5.8 (broad s, 2H),7.05 (d, 1H), 7.3 (s, 5H)].

By the same method, the 1-iodoethyl ester of the preceding Example isconverted to1-[6-beta-(D-2-azido-2-phenylacetamido)penicillanoyloxy]ethyl6'-beta-(hydroxymethyl)penicillanate 1',1'-dioxide.

Substituting an equivalent amount of the appropriate tetrabutylammoniumsalt (prepared by the same method from the corresponding penicillin),the following compounds are prepared from iodomethyl6-beta-(hydroxymethyl)penicillanate 1,1-dioxide:

6-beta-(2-phenylacetamido)penicillanoyloxymethyl6'-beta-(hydroxymethyl)penicillanate 1',1'-dioxide;

6-beta-(2-phenoxyacetamido)penicillanoyloxymethyl6'-beta-(hydroxymethyl)penicillanate 1',1'-dioxide;

6-beta-(2-benzyloxycarbonyl-2-phenylacetamido)penicillanoyloxymethyl6'-beta-(hydroxymethyl)penicillanate 1',1'-dioxide;

6-beta-[2-benzyloxycarbonyl-2-(2-thienyl)acetamido]penicillanoyloxymethyl6'-beta-(hydroxymethyl)penicillanate 1',1'-dioxide;

6-beta-[2-benzyloxycarbonyl-2-(3-thienyl)acetamido]penicillanoyloxymethyl6'-beta-(hydroxymethyl)penicillanate 1',1'-dioxide; and

6-beta-[2-(4-ethyl-2,3-dioxopiperazine-1-carboxamido)-2-phenylacetamido]penicillanoyloxymethyl6'-beta-(hydroxymethyl)penicillanate 1',1'-dioxide.

The title product is also prepared by reacting the correspondingchloromethyl, bromomethyl, mesyloxymethyl, benzenesulfonyloxymethyl andtosyloxymethyl esters of the preceding two Examples, monitoring thereaction by tlc and extending the reaction time as necessary. When thelatter esters are employed, it is preferable to add iodide ion toenhance the overall rate of conversion to the desired product.

EXAMPLE 7 6-beta-(D-2-Amino-2-phenylacetamido)penicillanoyloxymethyl6'-beta-(Hydroxymethyl)penicillanate 1',1'-Dioxide

Title compound of the preceding Example (1.4 g) was combined with 30 mlof methylene chloride and 30 ml of isopropyl alcohol and hydrogenated at50 psi for 45 minutes over 1.5 g of 10% Pd/C. Tlc control indicatedreaction to be about 75% complete. An additional portion (1.5 g) ofcatalyst was added and hydrogenation continued for 45 minutes. Since atrace of starting material remained, more catalyst (1 g) was added andhydrogenation allowed to proceed for a further 30 minutes. The catalystwas recovered by filtration with 1:1 methylene chloride:isopropylalcohol wash. The combined filtrate and washes were evaporated tosolids. The residue was triturated with ether and filtered to yield thetitle product [0.83 g; ir (nujol) 1735-1800 cm⁻¹ ; pnmr/DMSO-d₆/delta(ppm) 1.38, 1.39, 1.42 and 1.5 (4s, 12H), 3.6-4.35 (m, 3H), 4.42(s, 1H), 4.55 (s, 1H), 4.81 (s, 1H), 5.1-5.26 (m, 1H), 5.38-5.62 (m,2H), 5.9 (broad s, 2H), 7.4 (broad s, 5H)].

By the same method the corresponding 1,1-ethanediol bis-ester from thepreceding Example is converted to1-[6-beta-(D-2-amino-2-phenylacetamido)penicillanoyloxy]ethyl6'-beta-(hydroxymethyl)penicillanate 1',1'-dioxide.

By the same method the benzyl esters of the preceding Example arehydrogenolyzed to yield:

6-beta-(2-carboxy-2-phenylacetamido)penicillanoyloxymethyl6'-beta-(hydroxymethyl)penicillanate 1',1'-dioxide;

6-beta-[2-carboxy-2-(2-thienyl)acetamido]penicillanoyloxymethyl6'-beta-(hydroxymethyl)penicillanate 1',1'-dioxide; and

6-beta-[2-carboxy-2-(3-thienyl)acetamido]pencillanoyloxymethyl6'-beta-(hydroxymethyl)pencillanate 1',1'-dioxide.

EXAMPLE 8 6-beta-(D-2-Amino-2-phenylacetamido)penicillanoyloxymethyl6'-beta-(Hydroxymethyl)penicillanate 1',1'-Dioxide Hydrochloride

Hydrochloric acid (0.1 N, 12.5 ml) was cooled to 0° C. and 0.78 g of thecorresponding free base from the preceding Example added. The mixturewas stirred for 5 minutes to yield a hazy solution having pH 1.9. Thesolution was clarified by filtration over a pad of diatomaceous earthwith 30 ml water wash. The filtrate and wash were combined and freezedried to yield the title product [0.76 g; ir (nujol) 1730-1800 cm⁻¹ ;pnmr/DMSO-d₆ /delta(ppm) 1.2-1.62 (m, 12H), 3.5-4.3 (m, 3H), 4.38 (s,1H), 4.5 (s, 1H), 4.8-5.7 (m, 4H), 5.88 (broad s, 2H), 6.75 (d, 2H),7.22 (d, 2H), 8.5-9.1 (broad s, 2H), 9.4 (d, 1H), 9.8-10.2 (broad s,1H)].

EXAMPLE 96-beta-[D-2-Benzyloxycarbonylamino-2-(p-hydroxyphenyl)acetamido]penicillanoyloxymethyl6'-beta-(Hydroxymethyl)penicillanate 1',1'-Dioxide

6-beta-[D-2-Benzoyloxycarbonylamino-2-(p-hydroxyphenyl)acetamido]penicillanicacid ("carbobenzoxy amoxicillin", 5.0 g) was combined with 75 ml ofmethylene chloride and 25 ml of water. Gumming of the solids was noted.The pH was adjusted to 8.5 with 40% tetrabutylammonium hydroxide; thegummy solids dissolving. The methylene chloride layer was separated andthe aqueous layer extracted with two further 40 ml portions of methylenechloride. The methylene chloride organic layer and extracts werecombined and evaporated to yield the corresponding tetrabutylammoniumsalt (7.2 g).

Tetrabutylammonium salt prepared in this manner (3.33 g, 4.5 mmoles) wascombined with iodomethyl 6-beta-(hydroxymethyl)penicillanate 1,1-dioxide(1.25 g, 3.1 mmoles) in 15 ml of acetone. The reaction was monitored bytlc, which indicated almost complete reaction after 5 minutes and nomore than a trace of starting material after 30 minutes. The reactionmixture was concentrated in vacuo to a viscous gum. The residue wastaken up in 15 ml of 7:3 ethyl acetate:methylene chloride andchromatographed on 125 g of silica gel using the same solvent system aseluant and tlc monitoring. Product-containing fractions were combinedand evaporated to yield 1.8 g of partially purified product. The latterwas rechromatographed to yield purified title product [1.25 g; Rf 0.32(7:3 ethyl acetate:methylene chloride); pnmr/DMSO-d₆ /delta(ppm) 1.4,1.42, 1.48, 1.58 (4s, 12H), 3.55-4.3 (m, 3H), 4.4 (s, 1H), 4.59 (s, 1H),5.06 (s, 2H), 5.05-5.3 (m, 2H), 5.32-5.68 (m, 2H), 5.95 (broad s, 2H),6.68 (d, 2H), 7.2 (d, 2H), 7.34 (s, 5H), 7.78 (d, 1H), 8.9 (d, 1H), 9.4(s, 1H)].

In like manner, tetrabutylammonium salt is reacted with 1-iodoethyl6-beta-(hydroxymethyl)penicillanate 1,1-dioxide to produce thecorresponding bis 1,1-ethanediol ester.

In like manner, 6-beta-(benzyloxycarbonylamino)penicillanic acid isconverted to its tetrabutylammonium salt and then reacted withiodomethyl 6-beta-(hydroxymethyl)penicillanate 1,1-dioxide to yield6-beta-(benzyloxycarbonylamino)penicillanoyloxymethyl6'-beta-(hydroxymethyl)penicillanate 1',1'-dioxide.

EXAMPLE 106-beta-[D-2-Amino-2-(p-hydroxyphenyl)acetamido]penicillanoyloxymethyl6'-beta-(Hydroxymethyl)penicillanate 1',1'-Dioxide

The title ester of the preceding Example (1.2 g) was combined with 15 mlof isopropyl alcohol and 15 ml of methylene chloride and hydrogenated at50 psi over 1.5 g of 10% Pd/C for 45 minutes, at which time tlcmonitoring indicated the reaction was about 50% complete. An additional1.5 g of catalyst was added and hydrogenation continued for a further 45minutes to about 80% completion by tlc. A third 1.5 g portion ofcatalyst and 45 minutes hydrogenation left no more than a trace ofstarting material. The catalyst was recovered by filtration. Evaporationof the filtrate in vacuo to solids and trituration with ether gave thetitle product [0.42 g; pnmer/DMSO-d₆ /delta(ppm) 1.38, 1.42, 1.5 (s,12H), 3.5-4.25 (m, 3H), 4.38 (s, 1H), 4.52 (s, 1H), 4.8-5.7 (m, 4H),5.88 (broad s, 2H), 6.72 (d, 2H), 7.22 (d, 2H)].

In like manner, the bis 1,1-ethanediol ester of the preceding Example ishydrogenolyzed to the corresponding bis ester of 1,1-ethanediol withamoxicillin and 6-beta-(hydroxymethyl)penicillanate 1,1-dioxide.

In like manner, the 6-benzyloxycarbonylamino derivative of the precedingExample is hydrogenolyzed to yield 6-beta-aminopenicillanoyloxymethyl6'-beta-(hydroxymethyl)penicillanate 1,1-dioxide.

EXAMPLE 116-beta-[D-2-Amino-2-(p-hydroxyphenyl)acetamido]penicillanoyloxymethyl6'-beta-(Hydroxymethyl)penicillanate 1',1'-Dioxide Hydrochloride

By the procedure of Example 8, title product of the preceding Example(0.38 g) was converted to the title hydrochloride salt [0.33 g;pnmr/DMSO-d₆ /delta(ppm) 1.2-1.62 (m, 12H), 3.5-4.3 (m, 3H), 4.38 (s,1H), 4.5 (s, 1H), 4.8-5.7 (m, 4H), 5.88 (broad s, 2H), 6.75 (d, 2H),7.22 (d, 2H), 8.5-9.1 (broad s, 2H), 9.4 (d, 1H), 9.8-10.2 (broad s,1H)].

EXAMPLE 12 6-beta-(2-Phenylacetamido)penicillanoyloxymethyl6'-beta-(Hydroxymethyl)penicillanate 1',1'-Dioxide

6-beta-Aminopenicillanoyloxymethyl 6'-beta-(hydroxymethyl)penicillanate1',1'-dioxide of the preceding Example and a molar equivalent oftriethylamine are taken into 25 parts by weight of methylene chloride. Amolar equivalent of 2-phenylacetyl chloride in 5 parts by weight ofmethylene chloride is added dropwise while maintaining the temperatureof the reaction mixture at 20°-25° C. After 2 hours at the sametemperature, by-product triethylamine hydrochloride is extracted intowater. The methylene chloride layer is dried over anhydrous sodiumsulfate, filtered and evaporated to yield the title product.

EXAMPLE 136-beta-(2,2-Dimethyl-4-phenyl-5-imidazolidinon-1-yl)penicillanoyloxymethyl6'-beta-(Hydroxymethyl)penicillanate 1',1'-Dioxide

6-beta-(2-Amino-2-phenylacetamido)penicillanoyloxymethyl6'-beta-(hydroxymethyl)penicillanate 1',1'-dioxide (0.5 g) is stirredwith 30 ml of acetone for 3 days. The reaction mixture is evaporated invacuo to yield the title product.

EXAMPLE 14 Capsules

Capsules are prepared by blending the following ingredients in theproportion by weight indicated:

    ______________________________________                                        Calcium carbonate, U.S.P.                                                                             17.6                                                  Dicalcium phosphate     18.8                                                  Magnesium trisilicate, U.S.P.                                                                         5.2                                                   Lactose, U.S.P.         5.2                                                   Potato starch           5.2                                                   Magnesium stearate A    0.8                                                   Magnesium stearate B    0.35                                                  6-beta-(D-2-Amino-2-phenylacetamido)-                                         penicillanoyloxymethyl 6'-beta-                                               (hydroxymethyl)penicillanate 1',1'-                                           dioxide hydrochloride   50.0                                                  ______________________________________                                    

Appropriate weights of this blend are filled into gelatin capsules ofthe appropriate size so as to obtain capsules of the following potencyof the free base form of the active ingredient: 125 mg, 250 mg and 500mg.

I claim:
 1. A compound of the formula ##STR14## wherein R' is hydrogen or methyl.
 2. A compound of claim 1 wherein R' is hydrogen.
 3. A compound of the formula ##STR15## wherein n is zero or an integer of value 1 or 2; R' is hydrogen or methyl; and X is chloro, bromo, iodo, (C₁ -C₄)alkylsulfonyloxy, benzenesulfonyloxy or toluenesulfonyloxy.
 4. A compound of claim 3 wherein R' is hydrogen.
 5. The compound of claim 4 wherein n is zero and X is chloro.
 6. The compound of claim 4 wherein n is 1 and X is chloro.
 7. The compound of claim 4 wherein n is 2 and X is chloro.
 8. The compound of claim 4 wherein n is 2 and X is iodo.
 9. A compound of the formula ##STR16## wherein R' is hydrogen or methyl and X is chloro, bromo, iodo, (C₁ -C₄)alkylsulfonyloxy, benzenesulfonyloxy or toluenesulfonyloxy.
 10. The compound of claim 9 of the formula ##STR17## 